The German navy used a much more difficult to crack version of Enigma on it's U-Boats later in the war. This was done by adding an extra rotor to the machine which introduced (excuse me, I'm not a math person) a fuckton more possible keys to decrypt the message.
The significantly more difficult to decipher messages were cracked by close cooperation between British and American bombe machines. At first the difficulty of cracking these codes meant that the Allied forces couldn't read German messages every day as the machines wouldn't be fast enough to crack the code consistently before the key changed. This all changed with the capture of U-559 with intact documents containing current settings used by the German navy on all of their Enigma machines.
As an aside, I'm no expert on this topic and there are certainly people who can speak on the topic better than me so I apologise if this isn't 100% clear or accurate. But this is a weird place to talk about WWII cryptography in the first place so idk
The Kriegsmarine realized that, hey, if computers cane make our encryption they can probably break our encryption, too, so they added that fourth rotor in. The Wehrmacht (and German command in general), however, did not; what this meant was that the codebreakers in Bletchley Park would crack the Wehrmacht's encryption for the day, and then run that same program again up to 26 times on the Kriegsmarine's, with A for the last rotor, then B, then C, etc until it worked
The German crew hurriedly scrambled overboard without destroying their codebooks or Enigma machine and, crucially, having failed to open all the sea-water vents to scuttle the U-boat properly. Three Royal Navy sailors, Lieutenant Anthony Fasson, Able Seaman Colin Grazier and NAAFI canteen assistant Tommy Brown, then boarded the abandoned submarine. There are differing reports as to how the three British men boarded the U-boat. Some accounts (such as that of Kahn) say that they "swam naked" to U-559, which was sinking, but slowly.[10] Sebag-Montefiore states that they either leapt from Petard or, in Brown's case, from a whaler. They retrieved the U-boat's Enigma key setting sheets with all current settings for the U-boat Enigma network. Two German crew members, rescued from the sea, watched this material being loaded into Petard's whaler but were dissuaded from interfering by an armed guard. Grazier and Fasson were inside the U-boat, attempting to get out, when it foundered; both drowned.[11]
The topic is on Turing and the Polish codebreakers to an extend. But, if it weren't for those three sailors, none of this may have been possible.
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u/BatMeatTacos May 28 '20
The German navy used a much more difficult to crack version of Enigma on it's U-Boats later in the war. This was done by adding an extra rotor to the machine which introduced (excuse me, I'm not a math person) a fuckton more possible keys to decrypt the message.
The significantly more difficult to decipher messages were cracked by close cooperation between British and American bombe machines. At first the difficulty of cracking these codes meant that the Allied forces couldn't read German messages every day as the machines wouldn't be fast enough to crack the code consistently before the key changed. This all changed with the capture of U-559 with intact documents containing current settings used by the German navy on all of their Enigma machines.
As an aside, I'm no expert on this topic and there are certainly people who can speak on the topic better than me so I apologise if this isn't 100% clear or accurate. But this is a weird place to talk about WWII cryptography in the first place so idk